From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 0/3] state/exit_state cleanups (Was: Remove unused variable ret from sync_thread_master())
Date: Wed, 13 Nov 2013 15:35:52 +0100 [thread overview]
Message-ID: <20131113143552.GA10517@redhat.com> (raw)
On 11/12, Oleg Nesterov wrote:
>
> On 11/12, Peter Zijlstra wrote:
> >
> > We have to put in something...
> >
> > BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array));
> >
> > However, since we always set it together with TASK_UNINTERUPTIBLE
> > userspace shouldn't actually ever see the I thing.
>
> OOPS. I didn't know that get_task_state() does &= TASK_REPORT. So it
> can never report anything > EXIT_DEAD.
>
> Perhaps we should change BUILD_BUG_ON() and shrink task_state_array?
Seriously, imho this looks confusing enough and deserves a cleanup.
As for "nobody should use exit_state". I'll try to recheck, but iirc
we already discussed this... do you remember any reason why
schedule_debug() can't check prev->state == TASK_DEAD instead of
->exit_state?
Note that ->exit_state is not exactly right, it is set by exit_notify()
but in_atomic_preempt_off() should be only ignored when the task does
the last schedule() in TASK_DEAD.
Oleg.
next reply other threads:[~2013-11-13 14:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-13 14:35 Oleg Nesterov [this message]
2013-11-13 14:36 ` [PATCH 1/3] proc: cleanup/simplify get_task_state/task_state_array Oleg Nesterov
2013-11-13 14:36 ` [PATCH 2/3] fork: no need to initialize child->exit_state Oleg Nesterov
2013-11-27 14:10 ` [tip:sched/core] tasks/fork: Remove unnecessary child->exit_state tip-bot for Oleg Nesterov
2013-11-13 14:36 ` [PATCH 3/3] exit_state: kill task_is_dead() Oleg Nesterov
2013-11-27 14:10 ` [tip:sched/core] tasks/exit: Remove unused task_is_dead() method tip-bot for Oleg Nesterov
2013-11-13 14:48 ` [PATCH 0/3] state/exit_state cleanups (Was: Remove unused variable ret from sync_thread_master()) Peter Zijlstra
2013-11-13 14:50 ` Peter Zijlstra
2013-11-13 15:45 ` [PATCH 0/1] sched: Check TASK_DEAD rather than EXIT_DEAD in schedule_debug() Oleg Nesterov
2013-11-13 15:45 ` [PATCH 1/1] " Oleg Nesterov
2013-11-27 14:10 ` [tip:sched/core] " tip-bot for Oleg Nesterov
2013-11-13 15:58 ` [PATCH 0/1] " Peter Zijlstra
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